Mary’s room is an interesting one. I think there’s a valid rebuttal to it, though, but it takes quite a bit of explanation so hold onto your hats, ladies and gentlemen, and if you’re not interested then feel free to ignore. I should stress that this is an argument of my own formulation, although it is informed by my readings of a bunch of other philosophers, and that therefore it is entirely possible that people who share my conclusions might disagree with my premises or form of argument. I’m not trying very hard to convince anyone with this post, just putting the argument out there for your inspection. <-- (EDIT: left the word “not” out of this sentence the first time. Whoops!)
The hard-materialist, anti-qualian, functionalist argument is that sensation ≡ brain state. That is, “for one’s brain to be in the brain-state which is produced when red light hits one’s retina is to experience redness”. Once you’ve experienced redness a few times, it is to possible to intentionally assume that “red” brain-state, so it is possible to remember what it is like to see red without actually having to be exposed to red light. We call this “knowing what red is like”.
Mary, unfortunately, has grown up in a colour-free environment, so she has never experienced the brain-state that is “seeing red”, and even if her brain had drifted through that state accidentally, she wouldn’t have known that what she was experiencing was redness. She can’t find her way to the state of redness because she has never been there before. When she starts researching in an attempt to figure out what it is like to see red, her descriptive knowledge of the state will increase—she’ll know which sets of neurons are involved, the order and frequency of their firings, etc—but of course this won’t be much help in actually attaining a red brain-state. Hearing that Paris is at 48.8742° N, 2.3470° E doesn’t help you get there unless you know where you are right now.
Mary’s next step might be to investigate the patterns that instantiate sensations with which she is familiar. She might learn about how the smell of cinnamon is instantiated in the brain, or the feeling of heat, etc, etc, and then attempt to “locate” the sensation of red by analogy to these sensations. If you know where you are relative to Brisbane, and you know where Brisbane is relative to Paris, then you can figure out where you are relative to Paris.
This workaround would be effective if she were trying to find her way to a physical place, because on Earth you only need 3 dimensions to specify any given location, and it’s the same 3 dimensions every time. Unfortunately, the brain is more complicated. There are some patterns of neural behaviour which are only active in the perception of colour, so while analogy to the other senses might allow Mary zero in a little closer to knowing what red is like, it wouldn’t be nearly enough to solve her problem.
Luckily, Mary is a scientist, and where scientists can’t walk they generally invent a way to fly. Mary knows which neurons would are activated when people see red, and she knows the manner of their activation. She can scan her head and point to the region of her brain that red light would stimulate. So why does she need red light? Synesthetes regularly report colour experiences being induced by apparently non-coloured stimuli, and epileptics often experience phantom colours before fits. Ramachandran and Hubbard even offer a report of a colour-blind synesthete who experiences what he calls “Martian colours”—colours which he has never experienced in the real world and which therefore appear alien to him (PRSL, 2001). So, Mary CAN know red, she just has to induce the brain state associated with redness in herself. Maybe she uses transcranial electrostimulation. Maybe she has to resort to wireheading (http://wiki.lesswrong.com/wiki/Wireheading). Maybe all she needs to do is watch a real-time brain scan while she meditates, so she can learn to guide herself into the right state the same way that people who already “know” red get to it. Point is, if Mary is at all dedicated, she’s going to end up understanding red.
Of course, some qualians might argue that this misses the point—if Mary induces an experience of redness then she’s still exposing herself to the quale of red, whether or not there was any red light involved, so Mary hasn’t come to her knowledge solely by physical means. I think that skirts dangerously close to begging the question, though. As I’ve mentioned above, the functionalist view of colour holds that to know what it is like to see red is just “to know how to bring about the brain-state associated with redness in oneself”. It seems unfair to say that Mary has to be able possess that knowledge but never use it in order for functionalists to be proved right—you might as well request that she know what an elephant looks like without ever picturing one in her mind. Regardless, the Mary’s Room thought experiment presupposes that Mary can’t experience the quale of red in her colourless environment. If qualians want to argue that inducing the brain state of red exposes Mary to the quale of red, then the thought experiment doesn’t do what it was supposed to, and therefore can’t prove what it was designed to prove.
Anyway, I’d say that was my two cents but looking at how much I’ve typed it’s probably more like fifteen dollars...
Mary’s room is an interesting one. I think there’s a valid rebuttal to it, though, but it takes quite a bit of explanation so hold onto your hats, ladies and gentlemen, and if you’re not interested then feel free to ignore. I should stress that this is an argument of my own formulation, although it is informed by my readings of a bunch of other philosophers, and that therefore it is entirely possible that people who share my conclusions might disagree with my premises or form of argument. I’m not trying very hard to convince anyone with this post, just putting the argument out there for your inspection. <-- (EDIT: left the word “not” out of this sentence the first time. Whoops!)
The hard-materialist, anti-qualian, functionalist argument is that sensation ≡ brain state. That is, “for one’s brain to be in the brain-state which is produced when red light hits one’s retina is to experience redness”. Once you’ve experienced redness a few times, it is to possible to intentionally assume that “red” brain-state, so it is possible to remember what it is like to see red without actually having to be exposed to red light. We call this “knowing what red is like”.
Mary, unfortunately, has grown up in a colour-free environment, so she has never experienced the brain-state that is “seeing red”, and even if her brain had drifted through that state accidentally, she wouldn’t have known that what she was experiencing was redness. She can’t find her way to the state of redness because she has never been there before. When she starts researching in an attempt to figure out what it is like to see red, her descriptive knowledge of the state will increase—she’ll know which sets of neurons are involved, the order and frequency of their firings, etc—but of course this won’t be much help in actually attaining a red brain-state. Hearing that Paris is at 48.8742° N, 2.3470° E doesn’t help you get there unless you know where you are right now.
Mary’s next step might be to investigate the patterns that instantiate sensations with which she is familiar. She might learn about how the smell of cinnamon is instantiated in the brain, or the feeling of heat, etc, etc, and then attempt to “locate” the sensation of red by analogy to these sensations. If you know where you are relative to Brisbane, and you know where Brisbane is relative to Paris, then you can figure out where you are relative to Paris.
This workaround would be effective if she were trying to find her way to a physical place, because on Earth you only need 3 dimensions to specify any given location, and it’s the same 3 dimensions every time. Unfortunately, the brain is more complicated. There are some patterns of neural behaviour which are only active in the perception of colour, so while analogy to the other senses might allow Mary zero in a little closer to knowing what red is like, it wouldn’t be nearly enough to solve her problem.
Luckily, Mary is a scientist, and where scientists can’t walk they generally invent a way to fly. Mary knows which neurons would are activated when people see red, and she knows the manner of their activation. She can scan her head and point to the region of her brain that red light would stimulate. So why does she need red light? Synesthetes regularly report colour experiences being induced by apparently non-coloured stimuli, and epileptics often experience phantom colours before fits. Ramachandran and Hubbard even offer a report of a colour-blind synesthete who experiences what he calls “Martian colours”—colours which he has never experienced in the real world and which therefore appear alien to him (PRSL, 2001). So, Mary CAN know red, she just has to induce the brain state associated with redness in herself. Maybe she uses transcranial electrostimulation. Maybe she has to resort to wireheading (http://wiki.lesswrong.com/wiki/Wireheading). Maybe all she needs to do is watch a real-time brain scan while she meditates, so she can learn to guide herself into the right state the same way that people who already “know” red get to it. Point is, if Mary is at all dedicated, she’s going to end up understanding red.
Of course, some qualians might argue that this misses the point—if Mary induces an experience of redness then she’s still exposing herself to the quale of red, whether or not there was any red light involved, so Mary hasn’t come to her knowledge solely by physical means. I think that skirts dangerously close to begging the question, though. As I’ve mentioned above, the functionalist view of colour holds that to know what it is like to see red is just “to know how to bring about the brain-state associated with redness in oneself”. It seems unfair to say that Mary has to be able possess that knowledge but never use it in order for functionalists to be proved right—you might as well request that she know what an elephant looks like without ever picturing one in her mind. Regardless, the Mary’s Room thought experiment presupposes that Mary can’t experience the quale of red in her colourless environment. If qualians want to argue that inducing the brain state of red exposes Mary to the quale of red, then the thought experiment doesn’t do what it was supposed to, and therefore can’t prove what it was designed to prove.
Anyway, I’d say that was my two cents but looking at how much I’ve typed it’s probably more like fifteen dollars...